Does meat cause cancer?

It was all over the news last week: The WHO has classified red and processed meat as carcinogenic. At last. Anyone who follows nutrition research has known this for years and the American Institute for Cancer Research (AICR) has recommended a limit on meat for a long time, but it is not uncommon for news like this – which go against established views and are unpopular – to take years before being acknowledged by conventional medicine and to get published in the mainstream media. picture credit: Victor Hanacek, picjumbo

Unfortunately, the media seem to have created the wrong impression. Reading some of the headlines, you may be forgiven for thinking that meat-eating puts you at a high risk of colon cancer and that it is just as dangerous as smoking.

Not quite: The WHO ranks foods, drink, environmental toxins, etc. according to how confident they are that this substance causes cancer. The ranking says nothing about the level of risk. So, while smoking increases cancer risk by 2,500%, eating two slices of bacon a day increases your risk by 18%. The fact that both processed meat and smoking are classed as carcinogenic (Group 1) only means that the evidence for both is solid, that’s all.

What’s the relative risk?

Of 1,000 people in the UK, 61 will get bowel cancer at some point in their lives. People who consume small amounts or no meat have a lower risk: only 56 will develop bowel cancer. According to the research evaluated by the WHO, of those who eat a lot of meat, 66 are likely to develop bowel cancer. That’s 10 more than the group that does not consume a lot of meat. Every 50 g of processed meat increases the risk of bowel cancer by 18%, so the amount of meat matters quite a lot.

Which is the meat in question?

‘Processed’ meat is ranked in Group 1 (carcinogenic). By ‘processed’ meat they mean meat that is not sold fresh, but has been preserved in some way, ie cured, salted or smoked. This includes bacon, certain sausages, hot dogs, ham, salami, and pepperoni. But this doesn’t include fresh burgers or mince.

‘Red’ meat is the meat of beef, veal, pork, lamb, mutton, horse, and goat.

How does meat cause cancer?

Scientists are not entirely sure about the mechanism yet, but a promising hypothesis is based around N-nitroso compounds: Red meat, or rather the blood, contains a compound called ‘haem’ iron (the iron in plants is ‘non-haem’ iron), which through the process of digestion is converted into a group of chemicals called N-nitroso compounds. These can damage the cells of the intestinal lining, which in turn promotes the development of cancer. Red meat is classed in Group 2A (probably carcinogenic), because the evidence is not as strong.

N-nitroso compounds also form during processing, so overall, ‘processed’ meats expose the intestinal lining to more of these damaging chemicals, and this is why processed meats are considered more harmful and ranked in Group 1.

Moreover, cooking meat at high temperatures, e. g. frying and barbecuing, causes other chemical compounds to form, some of which are known or suspected carcinogens, so N-nitroso compounds are not the only problem.

Not mentioned in the recommendation are other carcinogenic features of meat. If you would like to read up on those, click here: It is the chapter on cancer from Dr Garth Davis’s book “Proteinaholic: How our obsession with meat is killing us and what we can do about it.”, which he has made available for free after last week's news headlines on meat.

So overall the WHO warning has been blown out of proportion in the media. Eating a couple of slices of bacon now and then does not mean that you are at an 18% risk of developing bowel cancer. It also is nowhere near as harmful as smoking. Still, it may be worth reconsidering your level of meat consumption, especially when you are already at a higher than average risk of colon cancer, e. g. if you have a history of colon cancer or a genetic predisposition for the disease.

There are also a whole host of other good reasons to limit or even avoid red meat, to name but a few:

The meat from conventionally raised cattle has an unfavourable fatty acid composition. As factory-farmed cattle is fed on grains rather than grass – the animals’ food of choice – it is higher in omega-6 fats than it would normally be. Most of us now get an unfavourable omega-6:omega-3 ratio from our diets, and meat from grain-fed cattle further contributes to that.

It costs the Earth: meat production is extremely damaging to the environment.

Animal welfare is non-existent in factory farms. By choosing organic meat, you are supporting a way of farming that is kinder to the animals – but they would probably prefer not to be eaten at all.

If you are going to eat meat, eat less of it. Make it organic and grass-fed, if at all possible.

If you'd rather cut back a bit or eat less meat, read tomorrow's Nutrilicious News, which will have my take on meat replacements and a recipe for a gorgeous meat-free Bolognese. There's still time to sign up.